Plants

10 pages, 707 KiB

Open AccessOpinion

Plant Sulfate Transporters in the Low Phytic Acid Network: Some Educated Guesses

by Gian Attilio Sacchi and Fabio Francesco Nocito

Plants 2019, 8(12), 616; https://doi.org/10.3390/plants8120616 - 17 Dec 2019

Cited by 10 | Viewed by 3636

A few new papers report that mutations in some genes belonging to the group 3 of plant sulfate transporter family result in low phytic acid phenotypes, drawing novel strategies and approaches for engineering the low-phytate trait in cereal grains. Here, we shortly review [...] Read more.

A few new papers report that mutations in some genes belonging to the group 3 of plant sulfate transporter family result in low phytic acid phenotypes, drawing novel strategies and approaches for engineering the low-phytate trait in cereal grains. Here, we shortly review the current knowledge on phosphorus/sulfur interplay and sulfate transport regulation in plants, to critically discuss some hypotheses that could help in unveiling the physiological links between sulfate transport and phosphorus accumulation in seeds. Full article

(This article belongs to the Special Issue Phytic Acid and Mineral Biofortification Strategies: From Plant Science to Breeding and Biotechnological Approaches)

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12 pages, 1807 KiB

Open AccessArticle

Soil Mesofauna Respond to the Upward Expansion of Deyeuxia purpurea in the Alpine Tundra of the Changbai Mountains, China

by Yan Tao, Zhongqiang Wang, Chen Ma, Hongshi He, Jiawei Xu, Yinghua Jin, Haixia Wang and Xiaoxue Zheng

Plants 2019, 8(12), 615; https://doi.org/10.3390/plants8120615 - 17 Dec 2019

Cited by 2 | Viewed by 1957

Abstract

Deyeuxia purpurea, a low-altitude species, has been expanding upwards into alpine tundra, and this upward expansion is causing serious ecological consequences. However, few studies have been performed regarding its effects on soil faunal communities. We examine how the upward expansion of D. [...] Read more.

Deyeuxia purpurea, a low-altitude species, has been expanding upwards into alpine tundra, and this upward expansion is causing serious ecological consequences. However, few studies have been performed regarding its effects on soil faunal communities. We examine how the upward expansion of D. purpurea affects the abundance, richness, and diversity of soil mesofauna, and evaluate how different taxa of soil mesofauna respond to the upward expansion of D. purpurea in the alpine tundra of Changbai Mountains, northeast China. A total of 128 soil mesofaunal samples were collected from four treatments, namely high upward expansion (HU), medium upward expansion (MU), low upward expansion (LU), and native plant habitats (NP). The results revealed that the abundance of soil mesofauna was increased with the rise of D. purpurea upward expansion, and the taxonomic composition varied with the different levels of D. purpurea upward expansion in the alpine tundra of the Changbai Mountains. No unique taxa were collected in the native plant habitats, and the upward expansion of D. purpurea promoted the colonization of predatory invertebrates. Isotomidae and Gamasida responded positively to the herbaceous plant upward expansion, and thus they were considered to be a positive indicator of upward expansion. Hypogastruridae and Enchytraeidae responded relatively negatively, while Oribatida, Actinedida, and Pseudachorutidae had ambivalent responses to the upward expansion. Overall, the abundance of soil mesofauna can indicate the levels of the upward expansion of D. purpurea. Soil mesofaunal guild characteristics were altered by the upward expansion. The different taxa of soil mesofauna responded to herbaceous plants’ upward expansion to various degrees. Therefore, this study provide evidence supporting the fact that the abundance of soil mesofauna can indicate the levels of upward expansion of D. purpurea, but the responses of soil mesofauna to the upward expansion of D. purpurea differ among their taxa. Full article

(This article belongs to the Section Plant Ecology)

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17 pages, 2869 KiB

Open AccessArticle

Transcriptomic Analysis of Dark-Induced Senescence in Bermudagrass (Cynodon dactylon)

by Jibiao Fan, Yanhong Lou, Haiyan Shi, Liang Chen and Liwen Cao

Plants 2019, 8(12), 614; https://doi.org/10.3390/plants8120614 - 17 Dec 2019

Cited by 10 | Viewed by 3074

Abstract

Leaf senescence induced by prolonged light deficiency is inevitable whenever turfgrass is cultivated in forests, and this negatively influences the survival and aesthetic quality of the turfgrass. However, the mechanism underlying dark-induced senescence in turfgrass remained obscure. In this study, RNA sequencing was [...] Read more.

Leaf senescence induced by prolonged light deficiency is inevitable whenever turfgrass is cultivated in forests, and this negatively influences the survival and aesthetic quality of the turfgrass. However, the mechanism underlying dark-induced senescence in turfgrass remained obscure. In this study, RNA sequencing was performed to analyze how genes were regulated in response to dark-induced leaf senescence in bermudagrass. A total of 159,207 unigenes were obtained with a mean length of 948 bp. The differential expression analysis showed that a total of 59,062 genes, including 52,382 up-regulated genes and 6680 down-regulated genes were found to be differentially expressed between control leaves and senescent leaves induced by darkness. Subsequent bioinformatics analysis showed that these differentially expressed genes (DEGs) were mainly related to plant hormone (ethylene, abscisic acid, jasmonic acid, auxin, cytokinin, gibberellin, and brassinosteroid) signal transduction, N-glycan biosynthesis, and protein processing in the endoplasmic reticulum. In addition, transcription factors, such as WRKY, NAC, HSF, and bHLH families were also responsive to dark-induced leaf senescence in bermudagrass. Finally, qRT-PCR analysis of six randomly selected DEGs validated the accuracy of sequencing results. Taken together, our results provide basic information of how genes respond to darkness, and contribute to the understanding of comprehensive mechanisms of dark-induced leaf senescence in turfgrass. Full article

(This article belongs to the Special Issue Leaf Senescence)

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15 pages, 5332 KiB

Open AccessArticle

Expression of Arabidopsis Hexokinase in Tobacco Guard Cells Increases Water-Use Efficiency and Confers Tolerance to Drought and Salt Stress

by Nitsan Lugassi, Brijesh Singh Yadav, Aiman Egbaria, Dalia Wolf, Gilor Kelly, Efrat Neuhaus, Eran Raveh, Nir Carmi and David Granot

Plants 2019, 8(12), 613; https://doi.org/10.3390/plants8120613 - 16 Dec 2019

Cited by 22 | Viewed by 3964

Abstract

Abiotic stresses such as drought and saline water impose major limitations on plant growth. Modulation of stomatal behavior may help plants cope with such stresses by reducing both water loss and salt uptake. Hexokinase (HXK) is a sugar-phosphorylating enzyme involved in guard cells’ [...] Read more.

Abiotic stresses such as drought and saline water impose major limitations on plant growth. Modulation of stomatal behavior may help plants cope with such stresses by reducing both water loss and salt uptake. Hexokinase (HXK) is a sugar-phosphorylating enzyme involved in guard cells’ sugar-sensing, mediating stomatal closure and coordinating photosynthesis with transpiration. We generated transgenic tobacco lines expressing the Arabidopsis hexokinase1 (AtHXK1) under the guard cell-specific promoter KST1 and examined those plants using growth room and greenhouse experiments. The expression of AtHXK1 in tobacco guard cells reduced stomatal conductance and transpiration by about 25% with no negative effects on photosynthesis or growth, leading to increased water-use efficiency. In addition, these plants exhibited tolerance to drought and salt stress due to their lower transpiration rate, indicating that improved stomatal function has the potential to improve plant performance under stress conditions. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

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20 pages, 5791 KiB

Open AccessArticle

Disentangling the Contributions of Plant Taxonomic and Functional Diversities in Shaping Aboveground Biomass of a Restored Forest Landscape in Southern China

by Md. Abu Hanif, Qingshui Yu, Xingquan Rao and Weijun Shen

Plants 2019, 8(12), 612; https://doi.org/10.3390/plants8120612 - 16 Dec 2019

Cited by 11 | Viewed by 3190

Abstract

Restoration is essential for supporting key ecosystem functions such as aboveground biomass production. However, the relative importance of functional versus taxonomic diversity in predicting aboveground biomass during restoration is poorly studied. Here, we used a trait-based approach to test for the importance of [...] Read more.

Restoration is essential for supporting key ecosystem functions such as aboveground biomass production. However, the relative importance of functional versus taxonomic diversity in predicting aboveground biomass during restoration is poorly studied. Here, we used a trait-based approach to test for the importance of multiple plant diversity attributes in regulating aboveground biomass in a 30-years-old restored subtropical forest in southern China. We show that both taxonomic and functional diversities are significant and positive regulators of aboveground biomass; however, functional diversity (FD) was more important than taxonomic diversity (species richness) in controlling aboveground biomass. FD had the strongest direct effect on aboveground biomass compared with species richness, soil nutrients, and community weighted mean (CWM) traits. Our results further indicate that leaf and root morphological traits and traits related to the nutrient content in plant tissues represent the existence of a leaf and root economic spectrum, and the acquisitive resource use strategy influenced aboveground biomass. Our results suggest that both taxonomic and FD play a role in shaping aboveground biomass, but FD is more important in supporting aboveground biomass in this type of environments. These results imply that enhancing FD is important to restoring and managing degraded forest landscapes. Full article

(This article belongs to the Special Issue 2019 Feature Papers by Plants’ Editorial Board Members)

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18 pages, 1310 KiB

Open AccessArticle

The Impact of Drought Stress on Antioxidant Responses and Accumulation of Flavonolignans in Milk Thistle (Silybum marianum (L.) Gaertn)

by Abdelaleim I. ElSayed, Mohamed A. M. El-hamahmy, Mohammed S. Rafudeen, Azza H. Mohamed and Ahmad A. Omar

Plants 2019, 8(12), 611; https://doi.org/10.3390/plants8120611 - 16 Dec 2019

Cited by 27 | Viewed by 3908

Abstract

Biosynthesis and accumulation of flavonolignans in plants are influenced by different environmental conditions. Biosynthesis and accumulation of silymarin in milk thistle (Silybum marianum L.) were studied under drought stress with respect to the antioxidant defense system at the physiological and gene expression [...] Read more.

Biosynthesis and accumulation of flavonolignans in plants are influenced by different environmental conditions. Biosynthesis and accumulation of silymarin in milk thistle (Silybum marianum L.) were studied under drought stress with respect to the antioxidant defense system at the physiological and gene expression level. The results revealed a reduction in leaf chlorophyll, ascorbic acid, and glutathione contents. In contrast, H₂O₂, proline, and antioxidative enzyme activities, such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR), were increased. These results confirmed that milk thistle undergoes oxidative stress under drought stress. Furthermore, transcription levels of APX, SOD, CAT, 1-Cys-Prx, and PrxQ were significantly increased in milk thistle under drought stress. Overall this suggests that protection against reactive oxygen species and peroxidation reactions in milk thistle are provided by enzymatic and non-enzymatic antioxidants. Flavonolignans from milk thistle seeds after different drought treatments were quantified by high-performance liquid chromatography (HPLC) and showed that severe drought stress enhanced the accumulation of silymarin and its components compared with seeds from the control (100% water capacity). Silybin is the major silymarin component and the most bioactive ingredient of the milk thistle extract. Silybin accumulation was the highest among all silymarin components in seeds obtained from drought-stressed plants. The expression of the chalcone synthase (CHS) genes (CHS1, CHS2, and CHS3), which are associated with the silybin biosynthetic pathway, was also increased during drought stress. These results indicated that milk thistle exhibits tolerance to drought stress and that seed derived from severe drought-stressed plants had higher levels of silymarin. Full article

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19 pages, 2673 KiB

Open AccessArticle

Melatonin Positively Influences the Photosynthetic Machinery and Antioxidant System of Avena sativa during Salinity Stress

by Nisha Varghese, Onoud Alyammahi, Sarah Nasreddine, Abla Alhassani and Mayank Anand Gururani

Plants 2019, 8(12), 610; https://doi.org/10.3390/plants8120610 - 16 Dec 2019

Cited by 43 | Viewed by 5006

Abstract

Recent studies have demonstrated melatonin protects various crops against abiotic stresses. However, the effects of melatonin on the photosynthetic apparatus of stressed plants is poorly characterized. We investigated the effects of melatonin pretreatment on photosynthesis and tolerance to salinity stress in Avena sativa [...] Read more.

Recent studies have demonstrated melatonin protects various crops against abiotic stresses. However, the effects of melatonin on the photosynthetic apparatus of stressed plants is poorly characterized. We investigated the effects of melatonin pretreatment on photosynthesis and tolerance to salinity stress in Avena sativa (oat) plants. Oat plants were exposed to four treatments (three replicate pots per treatment): well-watered (WW; control); watered with 300 mM salt solution for 10 days (NaCl); pretreated with 100 µM melatonin solution for 7 days then watered normally for 10 days (Mel+W); or pretreated with 100 µM melatonin for 7 days then 300 mM salt for 10 days (Mel+NaCl). Considerable differences in growth parameters, chlorophyll content, stomatal conductance, proline accumulation, lipid peroxidation, electrolyte leakage, and growth parameters were observed between groups. Genes encoding three major antioxidant enzymes were upregulated in the Mel+NaCl group compared to the other groups. Chlorophyll-a fluorescence kinetic analyses revealed that almost all photosynthetic parameters were improved in Mel+NaCl plants compared to the other treatments. Analysis of genes encoding the major extrinsic proteins of photosystem II (PSII) revealed that PsbA, PsbB, PsbC, and PsbD (but not PsbO) were highly upregulated in Mel+NaCl plants compared to the other groups, indicating melatonin positively influenced photosynthesis under control conditions and salt stress. In addition, melatonin upregulated stress-responsive NAC transcription factor genes in plants exposed to salt stress. These findings suggest melatonin pretreatment improves photosynthesis and enhances salt tolerance in oat plants. Full article

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12 pages, 3919 KiB

Open AccessArticle

Effect of Bioactive Phytochemicals from Phlomis viscosa Poiret on Wound Healing

by Ludmila Yarmolinsky, Arie Budovsky, Leonid Yarmolinsky, Boris Khalfin, Vladimir Glukhman and Shimon Ben-Shabat

Plants 2019, 8(12), 609; https://doi.org/10.3390/plants8120609 - 16 Dec 2019

Cited by 12 | Viewed by 2850

Abstract

Phlomis viscosa Poiret is an evergreen shrub growing in Israel, Turkey, Lebanon, and Syria with acknowledged pro-wound healing (WH) properties. In this study, we evaluated the pro-WH potential of selected compounds found in this plant. Among the pro-WH compounds (identified by us) was [...] Read more.

Phlomis viscosa Poiret is an evergreen shrub growing in Israel, Turkey, Lebanon, and Syria with acknowledged pro-wound healing (WH) properties. In this study, we evaluated the pro-WH potential of selected compounds found in this plant. Among the pro-WH compounds (identified by us) was a combination of three chemicals—diosmin, 1-octen-3-ol, and himachala-2,4-diene which enhanced WH significantly both in in vitro and in vivo models. The determined phytochemicals combination could be used for the treatment of chronic wounds. The effect of the extracts, diosmin, 1-octen-3-ol on the secretion of pro-inflammatory cytokines, IL-6 (A) and IL-8 (B) by human dermal fibroblasts was significant (p < 0.001). In addition, the beneficial effect of extracts of P. viscosa and its phytochemicals on WH was evidenced by inhibiting the growth of several WH delaying microorganisms. Full article

(This article belongs to the Special Issue Plant-Derived Chemicals: A Source of Inspiration for New Drugs)

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11 pages, 267 KiB

Open AccessEditor’s ChoiceArticle

United Forces of Botanical Oils: Efficacy of Neem and Karanja Oil against Colorado Potato Beetle under Laboratory Conditions

by Kateřina Kovaříková and Roman Pavela

Plants 2019, 8(12), 608; https://doi.org/10.3390/plants8120608 - 14 Dec 2019

Cited by 14 | Viewed by 4244

Abstract

Neem and karanja oil are the most promising botanical insecticides in crop protection nowadays. Given that information about the insecticidal abilities of these oils is lacking, the aim was to explore the effects of neem and karanja oil binary mixtures. The insecticidal activity [...] Read more.

Neem and karanja oil are the most promising botanical insecticides in crop protection nowadays. Given that information about the insecticidal abilities of these oils is lacking, the aim was to explore the effects of neem and karanja oil binary mixtures. The insecticidal activity of NeemAzal T/S (Trifolio-M GmbH, Lahnau, Germany) (neem oil), Rock Effect (Agro CS a.s., Česká Skalice, Czech Republic) (karanja oil), and their binary mixes (at 1:1, 1:2, and 2:1 volume ratios) against the larvae of the Colorado potato beetle (CPB; Leptinotarsa decemlineata) was studied. In our bioassays, a synergistic effect of the mixtures, which was dose-dependent, was observed for the first time against this pest. The most effective blend was the 1:1 ratio. Its efficacy was more or less the same as, or even greater than, the neem oil alone. The LC₅₀ of neem oil two days after application was (0.075 g·L⁻¹) and the LC₅₀ of the mixture was (0.065 g·L⁻¹). The LC₅₀ of karanja oil was (0.582 g·L⁻¹), which was much higher than the LC₅₀ of neem oil. The LC₉₀ of neem oil five days after application was (0.105 g·L⁻¹) and the LC₉₀ of the mixture was (0.037 g·L⁻¹). The LC₉₀ of karanja oil was (1.032 g·L⁻¹). The results demonstrate that it is possible to lower the doses of both oils and get improved efficacy against CPB larvae; nevertheless, further verification of the results in field conditions is necessary. Full article

(This article belongs to the Special Issue Pesticidal Plants: From Smallholder Use to Commercialisation)

14 pages, 685 KiB

Open AccessReview

Omics Potential in Herbicide-Resistant Weed Management

by Eric L. Patterson, Christopher Saski, Anita Küpper, Roland Beffa and Todd A. Gaines

Plants 2019, 8(12), 607; https://doi.org/10.3390/plants8120607 - 14 Dec 2019

Cited by 22 | Viewed by 5322

Abstract

The rapid development of omics technologies has drastically altered the way biologists conduct research. Basic plant biology and genomics have incorporated these technologies, while some challenges remain for use in applied biology. Weed science, on the whole, is still learning how to integrate [...] Read more.

The rapid development of omics technologies has drastically altered the way biologists conduct research. Basic plant biology and genomics have incorporated these technologies, while some challenges remain for use in applied biology. Weed science, on the whole, is still learning how to integrate omics technologies into the discipline; however, omics techniques are more frequently being implemented in new and creative ways to address basic questions in weed biology as well as the more practical questions of improving weed management. This has been especially true in the subdiscipline of herbicide resistance where important questions are the evolution and genetic basis of herbicide resistance. This review examines the advantages, challenges, potential solutions, and outlook for omics technologies in the discipline of weed science, with examples of how omics technologies will impact herbicide resistance studies and ultimately improve management of herbicide-resistant populations. Full article

(This article belongs to the Special Issue Herbicide Resistance in Plants)

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9 pages, 2073 KiB

Open AccessProtocol

Isolation of Intact Chloroplast for Sequencing Plastid Genomes of Five Festuca Species

by Md. Shofiqul Islam, Gretta L. Buttelmann, Konstantin Chekhovskiy, Taegun Kwon and Malay C. Saha

Plants 2019, 8(12), 606; https://doi.org/10.3390/plants8120606 - 14 Dec 2019

Cited by 5 | Viewed by 9087

Abstract

Isolation of good quality chloroplast DNA (cpDNA) is a challenge in different plant species, although several methods for isolation are known. Attempts were undertaken to isolate cpDNA from Festuca grass species by using available standard protocols; however, they failed due to difficulties separating [...] Read more.

Isolation of good quality chloroplast DNA (cpDNA) is a challenge in different plant species, although several methods for isolation are known. Attempts were undertaken to isolate cpDNA from Festuca grass species by using available standard protocols; however, they failed due to difficulties separating intact chloroplasts from the polysaccharides, oleoresin, and contaminated nuclear DNA that are present in the crude homogenate. In this study, we present a quick and inexpensive protocol for isolating intact chloroplasts from seven grass varieties/accessions of five Festuca species using a single layer of 30% Percoll solution. This protocol was successful in isolating high quality cpDNA with the least amount of contamination of other DNA. We performed Illumina MiSeq paired-end sequencing (2 × 300 bp) using 200 ng of cpDNA of each variety/accession. Chloroplast genome mapping showed that 0.28%–11.37% were chloroplast reads, which covered 94%–96% of the reference plastid genomes of the closely related grass species. This improved method delivered high quality cpDNA from seven grass varieties/accessions of five Festuca species and could be useful for other grass species with similar genome complexity. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

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23 pages, 1178 KiB

Open AccessReview

Research Progress on the Functions of Gasotransmitters in Plant Responses to Abiotic Stresses

by Yandong Yao, Yan Yang, Changxia Li, Dengjing Huang, Jing Zhang, Chunlei Wang, Weifang Li, Ni Wang, Yuzheng Deng and Weibiao Liao

Plants 2019, 8(12), 605; https://doi.org/10.3390/plants8120605 - 13 Dec 2019

Cited by 34 | Viewed by 3324

Abstract

Abiotic stress is one of the major threats affecting plant growth and production. The harm of abiotic stresses includes the disruption of cellular redox homeostasis, reactive oxygen species (ROS) production, and oxidative stress in the plant. Plants have different mechanisms to fight stress, [...] Read more.

Abiotic stress is one of the major threats affecting plant growth and production. The harm of abiotic stresses includes the disruption of cellular redox homeostasis, reactive oxygen species (ROS) production, and oxidative stress in the plant. Plants have different mechanisms to fight stress, and these mechanisms are responsible for maintaining the required homeostasis in plants. Recently, the study of gasotransmitters in plants has attracted much attention, especially for abiotic stress. In the present review, abiotic stressors were mostly found to induce gasotransmitter production in plants. Meanwhile, these gasotransmitters can enhance the activity of several antioxidant enzymes, alleviate the harmfulness of ROS, and enhance plant tolerance under various stress conditions. In addition, we introduced the interaction of gasotransmitters in plants under abiotic stress. With their promising applications in agriculture, gasotransmitters will be adopted in the near future. Full article

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17 pages, 4102 KiB

Open AccessArticle

The Quality Assessment of Commercial Lycium Berries Using LC-ESI-MS/MS and Chemometrics

by Mariam Jarouche, Harsha Suresh, James Hennell, Shaun Sullivan, Samiuela Lee, Swastika Singh, Declan Power, Cindy Xu and Cheang Khoo

Plants 2019, 8(12), 604; https://doi.org/10.3390/plants8120604 - 13 Dec 2019

Cited by 13 | Viewed by 2743

Abstract

Lycium (also known as Goji berry) is used in traditional Chinese medicine (TCM) with claimed benefits, including eye and liver protection, immune system fortification and blood glucose control. The commercially available product comes from either the L. barbarum or L. chinense species, with [...] Read more.

Lycium (also known as Goji berry) is used in traditional Chinese medicine (TCM) with claimed benefits, including eye and liver protection, immune system fortification and blood glucose control. The commercially available product comes from either the L. barbarum or L. chinense species, with the former dominating the marketplace due to its better taste profile. The main objective of this study was to develop a validated LC-ESI-MS/MS method to quantify multiple key bio-active analytes in commercially available Lycium berries and to qualitatively assess these samples using a principal component analysis (PCA). A LC-ESI-MS/MS method for the quantitation of seven analytes selected using the Herbal Chemical Marker Ranking System (Herb MaRS) was developed. The Herb MaRS ranking system considered bioavailability, bioactivity and physiological action of each target analyte, its intended use and the commercial availability of an analytical standard. After method optimization combining high resolving power with selective detection, seven analytes were quantified and the Lycium samples were quantitatively profiled. Chromatographic spectra were also obtained using longer run-time LC-UV and GC-MS methods in order to qualitatively assess the samples using a principal component analysis (PCA). The result of the method validation procedure was a 15.5 min LC-ESI-MS/MS method developed for the quantification of seven analytes in commercial Lycium samples. Wide variation in analyte concentration was observed with the following results (analyte range in mg/g): rutin, 16.1–49.2; narcissin, 0.37–1.65; nictoflorin, 0.26–0.78; coumaric acid, 6.84–12.2; scopoletin, 0.33–2.61; caffeic acid, 0.08–0.32; chlorogenic acid, 1.1–9.12. The quantitative results for the L. barbarum and L. chinense species samples indicate that they cannot be differentiated based on the bio-actives tested. A qualitative assessment using PCA generated from un-targeted LC-UV and GC-MS phytochemical spectra led to the same conclusion. The un-targeted quantitative and qualitative phytochemical profiling indicates that commercial L. barbarum and L. chinense cannot be distinguished using chemical analytical methods. Genetic fingerprinting and pharmacological testing may be needed to ensure the efficacy of commercial Lycium in order to validate label claims. Full article

(This article belongs to the Section Phytochemistry)

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17 pages, 5027 KiB

Open AccessArticle

Conjunctive Analyses of BSA-Seq and BSR-Seq to Reveal the Molecular Pathway of Leafy Head Formation in Chinese Cabbage

by Rui Li, Zhongle Hou, Liwei Gao, Dong Xiao, Xilin Hou, Changwei Zhang, Jiyong Yan and Lixiao Song

Plants 2019, 8(12), 603; https://doi.org/10.3390/plants8120603 - 13 Dec 2019

Cited by 14 | Viewed by 4093

Abstract

As the storage organ of Chinese cabbage, the leafy head was harvested as a commercial product due to its edible value. In this study, the bulked segregant analysis (BSA) and bulked segregant RNA-Seq (BSR) were performed with F₂ separation progeny to study [...] Read more.

As the storage organ of Chinese cabbage, the leafy head was harvested as a commercial product due to its edible value. In this study, the bulked segregant analysis (BSA) and bulked segregant RNA-Seq (BSR) were performed with F₂ separation progeny to study the molecular mechanism of leafy head formation in Chinese cabbage. BSA-Seq analysis located four candidate regions containing 40 candidate genes, while BSR-Seq analysis revealed eight candidate regions containing 607 candidate genes. The conjunctive analyses of these two methods identified that Casein kinase gene BrCKL8 (Bra035974) is the common candidate gene related with leafy head formation in Chinese cabbage, and it showed high expression levels at the three segments of heading type plant leaves. The differentially expressed genes (DEGs) between two set pairs of cDNA sequencing bulks were divided into two categories: one category was related with five hormone pathways (Auxin, Ethylene, Abscisic acid, Jasmonic acid and Gibberellin), the other category was composed of genes that associate with the calcium signaling pathway. Moreover, a series of upregulated transcriptional factors (TFs) were also identified by the association analysis of BSR-Seq analysis. The leafy head development was regulated by various biological processes and effected by diverse external environment factors, so our research will contribute to the breeding of perfect leaf-heading types of Chinese cabbage. Full article

(This article belongs to the Section Plant Development and Morphogenesis)

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18 pages, 2336 KiB

Open AccessArticle

The Effect of Abiotic Stress Conditions on Expression of Calmodulin (CaM) and Calmodulin-Like (CML) Genes in Wild-Growing Grapevine Vitis amurensis

by Alexandra S. Dubrovina, Olga A. Aleynova, Zlata V. Ogneva, Andrey R. Suprun, Alexey A. Ananev and Konstantin V. Kiselev

Plants 2019, 8(12), 602; https://doi.org/10.3390/plants8120602 - 13 Dec 2019

Cited by 29 | Viewed by 3045

Abstract

Plant calmodulins (CaMs) and calmodulin-like proteins (CMLs) are important plant Ca²⁺-binding proteins that sense and decode changes in the intracellular Ca²⁺ concentration arising in response to environmental stimuli. Protein Ca²⁺ sensors are presented by complex gene families in plants [...] Read more.

Plant calmodulins (CaMs) and calmodulin-like proteins (CMLs) are important plant Ca²⁺-binding proteins that sense and decode changes in the intracellular Ca²⁺ concentration arising in response to environmental stimuli. Protein Ca²⁺ sensors are presented by complex gene families in plants and perform diverse biological functions. In this study, we cloned, sequenced, and characterized three CaM and 54 CML mRNA transcripts of Vitis amurensis Rupr., a wild-growing grapevine with a remarkable stress tolerance. Using real-time quantitative RT-PCR, we analyzed transcript abundance of the identified VaCaMs and VaCMLs in response to water deficit, high salinity, high mannitol, cold and heat stresses. Expression of VaCaMs and 32 VaCMLs actively responded to the abiotic stresses and exhibited both positive and negative regulation patterns. Other VaCML members showed slight transcriptional regulation, remained essentially unresponsive or responded only after one time interval of the treatments. The substantial alterations in the VaCaM and VaCML transcript levels revealed their involvement in the adaptation of wild-growing grapevine to environmental stresses. Full article

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22 pages, 1273 KiB

Open AccessEditor’s ChoiceReview

Development of Improved Fruit, Vegetable, and Ornamental Crops Using the CRISPR/Cas9 Genome Editing Technique

by Lígia Erpen-Dalla Corte, Lamiaa M. Mahmoud, Tatiana S. Moraes, Zhonglin Mou, Jude W. Grosser and Manjul Dutt

Plants 2019, 8(12), 601; https://doi.org/10.3390/plants8120601 - 13 Dec 2019

Cited by 51 | Viewed by 10382

Abstract

Horticultural crops, including fruit, vegetable, and ornamental plants are an important component of the agriculture production systems and play an important role in sustaining human life. With a steady growth in the world’s population and the consequent need for more food, sustainable and [...] Read more.

Horticultural crops, including fruit, vegetable, and ornamental plants are an important component of the agriculture production systems and play an important role in sustaining human life. With a steady growth in the world’s population and the consequent need for more food, sustainable and increased fruit and vegetable crop production is a major challenge to guarantee future food security. Although conventional breeding techniques have significantly contributed to the development of important varieties, new approaches are required to further improve horticultural crop production. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) has emerged as a valuable genome-editing tool able to change DNA sequences at precisely chosen loci. The CRISPR/Cas9 system was developed based on the bacterial adaptive immune system and comprises of an endonuclease guided by one or more single-guide RNAs to generate double-strand breaks. These breaks can then be repaired by the natural cellular repair mechanisms, during which genetic mutations are introduced. In a short time, the CRISPR/Cas9 system has become a popular genome-editing technique, with numerous examples of gene mutation and transcriptional regulation control in both model and crop plants. In this review, various aspects of the CRISPR/Cas9 system are explored, including a general presentation of the function of the CRISPR/Cas9 system in bacteria and its practical application as a biotechnological tool for editing plant genomes, particularly in horticultural crops. Full article

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20 pages, 851 KiB

Open AccessArticle

Traditional Uses of Leguminosae among the Karen in Thailand

by Natcha Sutjaritjai, Prasit Wangpakapattanawong, Henrik Balslev and Angkhana Inta

Plants 2019, 8(12), 600; https://doi.org/10.3390/plants8120600 - 13 Dec 2019

Cited by 26 | Viewed by 7264

Abstract

Leguminosae (legumes) are one of the largest plant families. They are widely used for a variety of purposes by people around the world and include many important cultivated economic food crops. On local scales, legumes are commonly used by various ethnic groups. However, [...] Read more.

Leguminosae (legumes) are one of the largest plant families. They are widely used for a variety of purposes by people around the world and include many important cultivated economic food crops. On local scales, legumes are commonly used by various ethnic groups. However, the data are incomplete and scattered, not least in Thailand. We found that species of legumes were important in Karen communities, so we decided to investigate in detail the traditional knowledge of legumes on a local scale among Karen people in northern Thailand. We interviewed six herbalists and eighty-four nonherbalist informants in three Karen villages in Chiang Mai province about their use of legumes, and about the local names for the species, using semistructured interviews. A total of 83 legumes species (in 45 genera) had 4443 use reports. Five of the 83 legume species had not been reported previously as used in Thailand. Most Karen use reports (43%) of legumes were for food, medicine (36%), and materials (8%), but in term of species more legumes (68 species) were used for medicine than for food (53 species). The legume genera with most used species were Crotalaria and Flemingia each with six species. The most important species are Tamarindus indica (CI = 3.38), Senegalia rugata (CI = 2.39), Glycine max (CI = 1.27) respectively. Full article

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16 pages, 2972 KiB

Open AccessArticle

The Striking Flower-in-Flower Phenotype of Arabidopsis thaliana Nossen (No-0) is Caused by a Novel LEAFY Allele

by Anne Mohrholz, Hequan Sun, Nina Glöckner, Sabine Hummel, Üner Kolukisaoglu, Korbinian Schneeberger and Klaus Harter

Plants 2019, 8(12), 599; https://doi.org/10.3390/plants8120599 - 13 Dec 2019

Cited by 4 | Viewed by 3965

Abstract

The transition to reproduction is a crucial step in the life cycle of any organism. In Arabidopsis thaliana the establishment of reproductive growth can be divided into two phases: Firstly, cauline leaves with axillary meristems are formed and internode elongation begins. Secondly, lateral [...] Read more.

The transition to reproduction is a crucial step in the life cycle of any organism. In Arabidopsis thaliana the establishment of reproductive growth can be divided into two phases: Firstly, cauline leaves with axillary meristems are formed and internode elongation begins. Secondly, lateral meristems develop into flowers with defined organs. Floral shoots are usually determinate and suppress the development of lateral shoots. Here, we describe a transposon insertion mutant in the Nossen accession with defects in floral development and growth. Most strikingly is the outgrowth of stems from the axillary bracts of the primary flower carrying secondary flowers. Therefore, we named this mutant flower-in-flower (fif). However, the transposon insertion in the annotated gene is not the cause for the fif phenotype. By means of classical and genome sequencing-based mapping, the mutation responsible for the fif phenotype was found to be in the LEAFY gene. The mutation, a G-to-A exchange in the second exon of LEAFY, creates a novel lfy allele and results in a cysteine-to-tyrosine exchange in the α1-helix of LEAFY’s DNA-binding domain. This exchange abolishes target DNA-binding, whereas subcellular localization and homomerization are not affected. To explain the strong fif phenotype against these molecular findings, several hypotheses are discussed. Full article

(This article belongs to the Section Plant Development and Morphogenesis)

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14 pages, 304 KiB

Open AccessEditor’s ChoiceArticle

Comparative Evaluation of the Nutritive, Mineral, and Antinutritive Composition of Musa sinensis L. (Banana) and Musa paradisiaca L. (Plantain) Fruit Compartments

by Barnabas Oluwatomide Oyeyinka and Anthony Jide Afolayan

Plants 2019, 8(12), 598; https://doi.org/10.3390/plants8120598 - 12 Dec 2019

Cited by 53 | Viewed by 9897

Abstract

Banana and plantain contribute significantly to food security and amelioration of malnutrition, earning their status as staples in several localities of tropical and sub-tropical regions. The distribution of metabolites within the various parts also remains as a key essential to their nutritive and [...] Read more.

Banana and plantain contribute significantly to food security and amelioration of malnutrition, earning their status as staples in several localities of tropical and sub-tropical regions. The distribution of metabolites within the various parts also remains as a key essential to their nutritive and therapeutic potential. This study was aimed at evaluating the nutritional and mineral composition of the flesh, peel, and peel extract components of Musa sinensis L. and Musa paradisiaca L. fruits as well as their nutritional and therapeutic potentials. Proximate and antinutritional analyses were carried out using standard analytical methods of the Association of Official Analytical Chemists (AOAC), while the mineral constituents were evaluated using inductively coupled plasma optical emission spectroscopy (ICP-OES). Proximate analysis revealed that the flesh and peel of M. sinensis L. and M. paradisiaca L. contain substantial amounts of moisture, fiber, carbohydrates, and low fat content, while minerals K, Mg, Ca, Na, P, and N were substantially concentrated in the peels and peel extracts in particular. The antinutrients alkaloid, oxalate, saponin, and phytate were detected in safe amounts according to the World Health Organization (WHO). The study points out that the peel and its derivative extract, as well as the flesh of M. sinensis L. and M. paradisiaca L. are to be put to more relevant human nutritional and therapeutic use. Full article

(This article belongs to the Section Phytochemistry)

11 pages, 1631 KiB

Open AccessArticle

Phytochemical Analysis of Tephrosia vogelii across East Africa Reveals Three Chemotypes that Influence Its Use as a Pesticidal Plant

by Angela G. Mkindi, Yolice Tembo, Ernest R. Mbega, Beth Medvecky, Amy Kendal-Smith, Iain W. Farrell, Patrick A. Ndakidemi, Steven R. Belmain and Philip C. Stevenson

Plants 2019, 8(12), 597; https://doi.org/10.3390/plants8120597 - 12 Dec 2019

Cited by 14 | Viewed by 4530

Abstract

Tephrosia vogelii is a plant species chemically characterized by the presence of entomotoxic rotenoids and used widely across Africa as a botanical pesticide. Phytochemical analysis was conducted to establish the presence and abundance of the bioactive principles in this species across three countries [...] Read more.

Tephrosia vogelii is a plant species chemically characterized by the presence of entomotoxic rotenoids and used widely across Africa as a botanical pesticide. Phytochemical analysis was conducted to establish the presence and abundance of the bioactive principles in this species across three countries in East Africa: Tanzania, Kenya, and Malawi. Analysis of methanolic extracts of foliar parts of T. vogelii revealed the occurrence of two distinct chemotypes that were separated by the presence of rotenoids in one, and flavanones and flavones that are not bioactive against insects on the other. Specifically, chemotype 1 contained deguelin as the major rotenoid along with tephrosin, and rotenone as a minor component, while these compounds were absent from chemotype 2, which contained previously reported flavanones and flavones including obovatin-3-O-methylether. Chemotype 3 contained a combination of the chemical profiles of both chemotype 1 and 2 suggesting a chemical hybrid. Plant samples identified as chemotype 1 showed chemical consistency across seasons and altitudes, except in the wet season where a significant difference was observed for samples in Tanzania. Since farmers are unable to determine the chemical content of material available care must be taken in promoting this species for pest management without first establishing efficacy. While phytochemical analysis serves as an important tool for quality control of pesticidal plants, where analytical facilities are not available simple bioassays could be developed to enable extension staff and farmers to determine the efficacy of their plants and ensure only effective materials are adopted. Full article

(This article belongs to the Special Issue Pesticidal Plants: From Smallholder Use to Commercialisation)

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15 pages, 2917 KiB

Open AccessArticle

Anthocyanin in the Vacuole of Red Onion Epidermal Cells Quenches Other Fluorescent Molecules

by David A. Collings

Plants 2019, 8(12), 596; https://doi.org/10.3390/plants8120596 - 12 Dec 2019

Cited by 15 | Viewed by 7517

Abstract

Peels from the inner epidermis of onion bulbs are a model system in plant cell biology. While the inner epidermis of red onions is characteristically white, small patches of cells sometimes redden, containing vacuolar anthocyanin. This study investigated the spectroscopic properties of these [...] Read more.

Peels from the inner epidermis of onion bulbs are a model system in plant cell biology. While the inner epidermis of red onions is characteristically white, small patches of cells sometimes redden, containing vacuolar anthocyanin. This study investigated the spectroscopic properties of these anthocyanic cells. When fluorescent dyes were loaded into the vacuole of onion epidermal cells, the anthocyanic cells showed decreased dye fluorescence. This decrease was observed for fluorescein and carboxyfluorescein that are pumped into the vacuole by anion transporters, for acridine orange which acid loads into the vacuole, and for the fluorescent sugar analogue esculin loaded into the vacuole by sucrose transporters. Similar decreases in carboxyfluorescein fluorescence were observed when dye was loaded into the vacuoles of several other plant species, but decreases were not observed for dyes resident in the tonoplast membrane. As cellular physiology was unaffected in the anthocyanic cells, with cytoplasmic streaming, vacuolar and cytoplasmic pH not being altered, the decreased dye fluorescence from the anthocyanic cells can be attributed to fluorescence quenching. Furthermore, because quenching decreased with increasing temperature. It was concluded, therefore, that vacuolar anthocyanin can statically quench other fluorescent molecules in vivo, an effect previously demonstrated for anthocyanin in vitro. Full article

(This article belongs to the Special Issue Plant Flavonoids and Their Derivatives)

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22 pages, 1768 KiB

Open AccessReview

Plasmodesmata Conductivity Regulation: A Mechanistic Model

by Yuri L. Dorokhov, Natalia M. Ershova, Ekaterina V. Sheshukova and Tatiana V. Komarova

Plants 2019, 8(12), 595; https://doi.org/10.3390/plants8120595 - 12 Dec 2019

Cited by 21 | Viewed by 5925

Abstract

Plant cells form a multicellular symplast via cytoplasmic bridges called plasmodesmata (Pd) and the endoplasmic reticulum (ER) that crosses almost all plant tissues. The Pd proteome is mainly represented by secreted Pd-associated proteins (PdAPs), the repertoire of which quickly adapts to environmental conditions [...] Read more.

Plant cells form a multicellular symplast via cytoplasmic bridges called plasmodesmata (Pd) and the endoplasmic reticulum (ER) that crosses almost all plant tissues. The Pd proteome is mainly represented by secreted Pd-associated proteins (PdAPs), the repertoire of which quickly adapts to environmental conditions and responds to biotic and abiotic stresses. Although the important role of Pd in stress-induced reactions is universally recognized, the mechanisms of Pd control are still not fully understood. The negative role of callose in Pd permeability has been convincingly confirmed experimentally, yet the roles of cytoskeletal elements and many PdAPs remain unclear. Here, we discuss the contribution of each protein component to Pd control. Based on known data, we offer mechanistic models of mature leaf Pd regulation in response to stressful effects. Full article

(This article belongs to the Section Plant Cell Biology)

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16 pages, 3047 KiB

Open AccessArticle

Transgressivity in Key Functional Traits Rather Than Phenotypic Plasticity Promotes Stress Tolerance in A Hybrid Cordgrass

by Blanca Gallego-Tévar, Brenda J. Grewell, Rebecca E. Drenovsky and Jesús M. Castillo

Plants 2019, 8(12), 594; https://doi.org/10.3390/plants8120594 - 12 Dec 2019

Cited by 1 | Viewed by 2721

Abstract

Hybridization might promote offspring fitness via a greater tolerance to environmental stressors due to heterosis and higher levels of phenotypic plasticity. Thus, analyzing the phenotypic expression of hybrids provides an opportunity to elucidate further plant responses to environmental stress. In the case of [...] Read more.

Hybridization might promote offspring fitness via a greater tolerance to environmental stressors due to heterosis and higher levels of phenotypic plasticity. Thus, analyzing the phenotypic expression of hybrids provides an opportunity to elucidate further plant responses to environmental stress. In the case of coastal salt marshes, sea level rise subjects hybrids, and their parents, to longer tidal submergence and higher salinity. We analyzed the phenotypic expression patterns in the hybrid Spartina densiflora x foliosa relative to its parental species, native S. foliosa, and invasive S. densiflora, from the San Francisco Estuary when exposed to contrasting salinities and inundations in a mesocosm experiment. 37% of the recorded traits displayed no variability among parents and hybrids, 3% showed an additive inheritance, 37% showed mid-parent heterosis, 18% showed best-parent heterosis, and 5% presented worst-parent heterosis. Transgressivity, rather than phenotypic plasticity, in key functional traits of the hybrid, such as tiller height, conveyed greater stress tolerance to the hybrid when compared to the tolerance of its parents. As parental trait variability increased, phenotypic transgressivity of the hybrid increased and it was more important in response to inundation than salinity. Increases in salinity and inundation associated with sea level rise will amplify the superiority of the hybrid over its parental species. These results provide evidence of transgressive traits as an underlying source of adaptive variation that can facilitate plant invasions. The adaptive evolutionary process of hybridization is thought to support an increased invasiveness of plant species and their rapid evolution. Full article

(This article belongs to the Special Issue Plants Heterosis)

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15 pages, 1830 KiB

Open AccessArticle

Understanding the Environmental Background of an Invasive Plant Species (Asclepias syriaca) for the Future: An Application of LUCAS Field Photographs and Machine Learning Algorithm Methods

by Péter Szilassi, Gábor Szatmári, László Pásztor, Mátyás Árvai, József Szatmári, Katalin Szitár and Levente Papp

Plants 2019, 8(12), 593; https://doi.org/10.3390/plants8120593 - 12 Dec 2019

Cited by 15 | Viewed by 4294

Abstract

For developing global strategies against the dramatic spread of invasive species, we need to identify the geographical, environmental, and socioeconomic factors determining the spatial distribution of invasive species. In our study, we investigated these factors influencing the occurrences of common milkweed (Asclepias [...] Read more.

For developing global strategies against the dramatic spread of invasive species, we need to identify the geographical, environmental, and socioeconomic factors determining the spatial distribution of invasive species. In our study, we investigated these factors influencing the occurrences of common milkweed (Asclepias syriaca L.), an invasive plant species that is of great concern to the European Union (EU). In a Hungarian study area, we used country-scale soil and climate databases, as well as an EU-scale land cover databases (CORINE) for the analyses. For the abundance data of A. syriaca, we applied the field survey photos from the Land Use and Coverage Area Frame Survey (LUCAS) Land Cover database for the European Union. With machine learning algorithm methods, we quantified the relative weight of the environmental variables on the abundance of common milkweed. According to our findings, soil texture and soil type (sandy soils) were the most important variables determining the occurrence of this species. We could exactly identify the actual land cover types and the recent land cover changes that have a significant role in the occurrence the common milkweed in Europe. We could also show the role of climatic conditions of the study area in the occurrence of this species, and we could prepare the potential distribution map of common milkweed for the study area. Full article

(This article belongs to the Special Issue Invasive Plants)

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20 pages, 1613 KiB

Open AccessEditor’s ChoiceReview

Integration of Abscisic Acid Signaling with Other Signaling Pathways in Plant Stress Responses and Development

by Manu Kumar, Mahipal Singh Kesawat, Asjad Ali, Sang-Choon Lee, Sarvajeet Singh Gill and Hyun Uk Kim

Plants 2019, 8(12), 592; https://doi.org/10.3390/plants8120592 - 11 Dec 2019

Cited by 80 | Viewed by 10500

Abstract

Plants are immobile and, to overcome harsh environmental conditions such as drought, salt, and cold, they have evolved complex signaling pathways. Abscisic acid (ABA), an isoprenoid phytohormone, is a critical signaling mediator that regulates diverse biological processes in various organisms. Significant progress has [...] Read more.

Plants are immobile and, to overcome harsh environmental conditions such as drought, salt, and cold, they have evolved complex signaling pathways. Abscisic acid (ABA), an isoprenoid phytohormone, is a critical signaling mediator that regulates diverse biological processes in various organisms. Significant progress has been made in the determination and characterization of key ABA-mediated molecular factors involved in different stress responses, including stomatal closure and developmental processes, such as seed germination and bud dormancy. Since ABA signaling is a complex signaling network that integrates with other signaling pathways, the dissection of its intricate regulatory network is necessary to understand the function of essential regulatory genes involved in ABA signaling. In the present review, we focus on two aspects of ABA signaling. First, we examine the perception of the stress signal (abiotic and biotic) and the response network of ABA signaling components that transduce the signal to the downstream pathway to respond to stress tolerance, regulation of stomata, and ABA signaling component ubiquitination. Second, ABA signaling in plant development processes, such as lateral root growth regulation, seed germination, and flowering time regulation is investigated. Examining such diverse signal integration dynamics could enhance our understanding of the underlying genetic, biochemical, and molecular mechanisms of ABA signaling networks in plants. Full article

(This article belongs to the Special Issue 2019 Feature Papers by Plants’ Editorial Board Members)

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17 pages, 3133 KiB

Open AccessArticle

New Insight into HPts as Hubs in Poplar Cytokinin and Osmosensing Multistep Phosphorelays: Cytokinin Pathway Uses Specific HPts

by François Héricourt, Mélanie Larcher, Françoise Chefdor, Konstantinos Koudounas, Inês Carqueijeiro, Pamela Lemos Cruz, Vincent Courdavault, Mirai Tanigawa, Tatsuya Maeda, Christiane Depierreux, Frédéric Lamblin, Gaëlle Glévarec and Sabine Carpin

Plants 2019, 8(12), 591; https://doi.org/10.3390/plants8120591 - 11 Dec 2019

Cited by 11 | Viewed by 3219

Abstract

We have previously identified proteins in poplar which belong to an osmosensing (OS) signaling pathway, called a multistep phosphorelay (MSP). The MSP comprises histidine-aspartate kinases (HK), which act as membrane receptors; histidine phosphotransfer (HPt) proteins, which act as phosphorelay proteins; and response regulators [...] Read more.

We have previously identified proteins in poplar which belong to an osmosensing (OS) signaling pathway, called a multistep phosphorelay (MSP). The MSP comprises histidine-aspartate kinases (HK), which act as membrane receptors; histidine phosphotransfer (HPt) proteins, which act as phosphorelay proteins; and response regulators (RR), some of which act as transcription factors. In this study, we identified the HK proteins homologous to the Arabidopsis cytokinin (CK) receptors, which are first partners in the poplar cytokinin MSP, and focused on specificity of these two MSPs (CK and OS), which seem to share the same pool of HPt proteins. Firstly, we isolated five CK HKs from poplar which are homologous to Arabidopsis AHK2, AHK3, and AHK4, namely, HK2, HK3a, HK3b, HK4a, HK4b. These HKs were shown to be functional kinases, as observed in a functional complementation of a yeast HK deleted strain. Moreover, one of these HKs, HK4a, was shown to have kinase activity dependent on the presence of CK. Exhaustive interaction tests between these five CK HKs and the 10 HPts characterized in poplar were performed using two-hybrid and BiFC experiments. The resulting partnership was compared to that previously identified between putative osmosensors HK1a/1b and HPt proteins. Finally, in planta coexpression analysis of genes encoding these potential partners revealed that almost all HPts are coexpressed with CK HKs in four different poplar organs. Overall, these results allowed us to unravel the common and specific partnerships existing between OS and CK MSP in Populus. Full article

(This article belongs to the Special Issue The Plant Two-Component System)

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21 pages, 795 KiB

Open AccessReview

New Insights into Multistep-Phosphorelay (MSP)/Two-Component System (TCS) Regulation: Are Plants and Bacteria That Different?

by Virtudes Mira-Rodado

Plants 2019, 8(12), 590; https://doi.org/10.3390/plants8120590 - 11 Dec 2019

Cited by 20 | Viewed by 4428

Abstract

The Arabidopsis multistep-phosphorelay (MSP) is a signaling mechanism based on a phosphorelay that involves three different types of proteins: Histidine kinases, phosphotransfer proteins, and response regulators. Its bacterial equivalent, the two-component system (TCS), is the most predominant device for signal transduction in prokaryotes. [...] Read more.

The Arabidopsis multistep-phosphorelay (MSP) is a signaling mechanism based on a phosphorelay that involves three different types of proteins: Histidine kinases, phosphotransfer proteins, and response regulators. Its bacterial equivalent, the two-component system (TCS), is the most predominant device for signal transduction in prokaryotes. The TCS has been extensively studied and is thus generally well-understood. In contrast, the MSP in plants was first described in 1993. Although great advances have been made, MSP is far from being completely comprehended. Focusing on the model organism Arabidopsis thaliana, this review summarized recent studies that have revealed many similarities with bacterial TCSs regarding how TCS/MSP signaling is regulated by protein phosphorylation and dephosphorylation, protein degradation, and dimerization. Thus, comparison with better-understood bacterial systems might be relevant for an improved study of the Arabidopsis MSP. Full article

(This article belongs to the Special Issue The Plant Two-Component System)

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18 pages, 1609 KiB

Open AccessArticle

Secoiridoids Metabolism Response to Wounding in Common Centaury (Centaurium erythraea Rafn) Leaves

by Jelena Božunović, Marijana Skorić, Dragana Matekalo, Suzana Živković, Milan Dragićević, Neda Aničić, Biljana Filipović, Tijana Banjanac, Branislav Šiler and Danijela Mišić

Plants 2019, 8(12), 589; https://doi.org/10.3390/plants8120589 - 11 Dec 2019

Cited by 8 | Viewed by 3599

Abstract

Centaurium erythraea Rafn produces and accumulates various biologically active specialized metabolites, including secoiridoid glucosides (SGs), which help plants to cope with unfavorable environmental conditions. Specialized metabolism is commonly modulated in a way to increase the level of protective metabolites, such as SGs. Here, [...] Read more.

Centaurium erythraea Rafn produces and accumulates various biologically active specialized metabolites, including secoiridoid glucosides (SGs), which help plants to cope with unfavorable environmental conditions. Specialized metabolism is commonly modulated in a way to increase the level of protective metabolites, such as SGs. Here, we report the molecular background of the wounding-induced changes in SGs metabolism for the first time. The mechanical wounding of leaves leads to a coordinated up-regulation of SGs biosynthetic genes and corresponding JA-related transcription factors (TFs) after 24 h, which results in the increase of metabolic flux through the biosynthetic pathway and, finally, leads to the elevated accumulation of SGs 96 h upon injury. The most pronounced increase in relative expression was detected for secologanin synthase (CeSLS), highlighting this enzyme as an important point for the regulation of biosynthetic flux through the SG pathway. A similar expression pattern was observed for CeBIS1, imposing itself as the TF that is prominently involved in wound-induced regulation of SGs biosynthesis genes. The high degree of positive correlations between and among the biosynthetic genes and targeted TFs expressions indicate the transcriptional regulation of SGs biosynthesis in response to wounding with a significant role of CeBIS1, which is a known component of the jasmonic acid (JA) signaling pathway. Full article

(This article belongs to the Special Issue 2019 Feature Papers by Plants’ Editorial Board Members)

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17 pages, 4455 KiB

Open AccessArticle

Seed Pretreatment and Foliar Application of Proline Regulate Morphological, Physio-Biochemical Processes and Activity of Antioxidant Enzymes in Plants of Two Cultivars of Quinoa (Chenopodium quinoa Willd.)

by Hira Yaqoob, Nudrat A. Akram, Samrah Iftikhar, Muhammad Ashraf, Noman Khalid, Muhammad Sadiq, Mohammed Nasser Alyemeni, Leonard Wijaya and Parvaiz Ahmad

Plants 2019, 8(12), 588; https://doi.org/10.3390/plants8120588 - 10 Dec 2019

Cited by 18 | Viewed by 3639

Abstract

In the current study, the effects of exogenously applied proline (25 and 50 mM) and low-temperature treatment were examined on the physiochemical parameters in the plants of two cultivars (V₁ and V₂) of quinoa (Chenopodium quinoa Willd.). The seeds [...] Read more.

In the current study, the effects of exogenously applied proline (25 and 50 mM) and low-temperature treatment were examined on the physiochemical parameters in the plants of two cultivars (V₁ and V₂) of quinoa (Chenopodium quinoa Willd.). The seeds were also exposed to chilling stress at 4 °C before sowing. Plants raised from the seeds treated with low temperature showed reduced plant growth and contents of chlorophyll and carotenoids, but they had significantly increased contents of malondialdehyde, proline, ascorbic acid, total free amino acids, total soluble sugars, and total phenolics, as well as the activity of the peroxidase (POD) enzyme. Cold stress applied to seeds remained almost ineffective in terms of bringing about changes in plant root, hydrogen peroxide, glycine betaine and activities of superoxide dismutase (SOD), and catalase (CAT) enzymes. The exogenous application of proline significantly increased plant growth, the contents of chlorophyll, carotenoids, proline, ascorbic acid, total free amino acids, phenolics, and total soluble sugars, as well as the activities of SOD, POD, and CAT, but it decreased malondialdehyde content. Overall, foliar application of proline was better than the seed treatment in improving root dry weight, root length, chlorophyll a, carotenoids, glycine betaine, ascorbic acid and superoxide dismutase activity, whereas seed pre-treatment with proline was effective in improving shoot dry weight, shoot length, hydrogen peroxide, malondialdehyde, and peroxidase activity in both quinoa cultivars. Full article

(This article belongs to the Special Issue Adaptation of Plants to Environmental Changes: Light and Temperature in Plant Development)

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14 pages, 4610 KiB

Open AccessArticle

An Exploration of Common Greenhouse Gas Emissions by the Cyanobiont of the Azolla–Nostoc Symbiosis and Clues as to Nod Factors in Cyanobacteria

by Dilantha Gunawardana

Plants 2019, 8(12), 587; https://doi.org/10.3390/plants8120587 - 10 Dec 2019

Cited by 5 | Viewed by 3874

Abstract

Azolla is a genus of aquatic ferns that engages in a unique symbiosis with a cyanobiont that is resistant to cultivation. Azolla spp. are earmarked as a possible candidate to mitigate greenhouse gases, in particular, carbon dioxide. That opinion is underlined here in [...] Read more.

Azolla is a genus of aquatic ferns that engages in a unique symbiosis with a cyanobiont that is resistant to cultivation. Azolla spp. are earmarked as a possible candidate to mitigate greenhouse gases, in particular, carbon dioxide. That opinion is underlined here in this paper to show the broader impact of Azolla spp. on greenhouse gas mitigation by revealing the enzyme catalogue in the Nostoc cyanobiont to be a poor contributor to climate change. First, regarding carbon assimilation, it was inferred that the carboxylation activity of the Rubisco enzyme of Azolla plants is able to quench carbon dioxide on par with other C₃ plants and fellow aquatic free-floating macrophytes, with the cyanobiont contributing on average ~18% of the carboxylation load. Additionally, the author demonstrates here, using bioinformatics and past literature, that the Nostoc cyanobiont of Azolla does not contain nitric oxide reductase, a key enzyme that emanates nitrous oxide. In fact, all Nostoc species, both symbiotic and nonsymbiotic, are deficient in nitric oxide reductases. Furthermore, the Azolla cyanobiont is negative for methanogenic enzymes that use coenzyme conjugates to emit methane. With the absence of nitrous oxide and methane release, and the potential ability to convert ambient nitrous oxide into nitrogen gas, it is safe to say that the Azolla cyanobiont has a myriad of features that are poor contributors to climate change, which on top of carbon dioxide quenching by the Calvin cycle in Azolla plants, makes it an efficient holistic candidate to be developed as a force for climate change mitigation, especially in irrigated urea-fed rice fields. The author also shows that Nostoc cyanobionts are theoretically capable of Nod factor synthesis, similar to Rhizobia and some Frankia species, which is a new horizon to explore in the future. Full article

(This article belongs to the Special Issue Nitrogen-Fixing Plants )

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